Recent developments in industry have shown that Radio Frequency Identification Systems (RFID-systems) are becoming an integrated part of logistics and transportation applications. On one hand such RFID-systems typically comprise at least one data carrier, which data carrier comprises an integrated circuit and transmission means that are connected to the integrated circuit. On the other hand such RFID-systems comprise a read/write station, also known as RFID reader, that provides a Radio Frequency (RF) carrier signal for the purpose of powering the integrated circuit of the data carrier and for exchanging data with said integrated data carrier by the aid of the RF carrier signal in a contactless manner. Due to increasing demand for long distance RFID-systems the domain of Ultra High Frequency (UHF) RFID-systems that operate up to the GHz frequency range is recently becoming very important for such logistics and transportation applications.
During manufacturing of said circuits and data carriers comprising the circuits it is necessary to carry out various functional tests. These functional tests comprise self-tests of the integrated circuits and the data carriers, respectively.
German patent DE 100 15 484 C2 discloses a test system for integrated circuits that are carried on a wafer wherein the self-tests of the circuits have to be carried out prior to separating the integrated circuits from the wafer. This known test system comprises a reading head that is adapted to send electromagnetic signals in a wireless manner to the integrated circuits in order to selectively activate them. When being activated the integrated circuits carry out the self-tests and reply to the testing head only if the self-tests have been successful. The testing heads evaluate the received replies.
The known test system, however, is only useful for testing integrated circuits before they are separated from the waver. Thus, it is not applicable after manufacturing steps of separating the integrated circuits from the waver, fixing them to a substrate and bonding them to an antenna have been carried out. In practice, this is a big disadvantage, since it has turned out that the manufacturing steps of separating the integrated circuits from the wafers and fixing them on a substrate are those with the highest risk for damaging the integrated circuits. Further, DE 100 15 484 C2 does not reveal any measures to trigger the self-tests of the integrated circuits. Specifically, this document does not suggest to use voltages that are different from the conventional RF electromagnetic signals to trigger self-tests of the integrated circuits. Further, the use of testing heads that transmit and receive RF electromagnetic signals require the use of relatively expensive test equipment for testing the integrated circuits.